Fig. 2　Cytogenetic characteristics of hydatidiform moles. (A) Complete hydatidiform mole (CHM) is an androgenetic diploid, classified into two types: homozygous CHM, which results from the duplication of a haploid sperm; and heterozygous CHM, which results from the fertilization of two mature sperms. (B) Partial hydatidiform mole (PHM) is diandric monogyny triploid. (C) Non-molar villous trophoblasts are biparental diploids. (Figure 2 was adapted from reference No. 8 by Usui, 2022.) CHM, complete hydatidiform mole; PHM, partial hydatidiform mole